AL-Rashidi, Alyah (Kuwait Oil Company) | Jain, Manish (Kuwait Oil Company) | Tirkey, Naween (Kuwait Oil Company) | AL-Ammar, Heyam (Kuwait Oil Company) | Al-Ajmi, Salem (Kuwait Oil Company) | Weiss, Adrian (British Petroleum)
Greater Burgan Field has been producing from more than 70 years and brings many challenges with the maturing field. During the last decade almost all the new wells drilled were completed as dual completions to simultaneously produce from two different formations in Burgan. As the workover rig activity tremendously increased with the increased number of new wells per year, it has been a constant endeavor to carry out maximum well intervention jobs possibly by rig less operations to reduce rig related OPEX and well production down time during rig work over.
One of the biggest long term challenges was to carry out well interventions in dual completions short tubing, which was used to be considered inaccessible due to presence of tubing long in the well bore. In view of above, most of the intended well interventions in tubing short were normally used to be proclaimed as work over candidate thereby increasing load on limited work over rigs.
First time in Burgan a dual completion well was carefully identified to carry out water shut off job by chemical application and adding perforation by oriented perforation gun in short tubing. The tubing short was producing from BGSU reservoir and became ceased to flow due to lateral water encroachment which was evident from the recent PNC log. The formation layer below BGSM was still having oil potential and was intended to produce after shutting off the upper layer BGSU. The Tubing Long was producing from deeper reservoir BGSL around 1200 BLPD with 50% W/C.
This paper elaborates the procedures adopted during the execution of the job and selection process of the chemical squeeze technology. The best suitable chemical technology was selected after carrying out a careful & detailed approach towards different vendors. The step by step detailed program was prepared to squeeze the chemical in to existing perforations, cleaning to the desired depth, testing the squeezed perforations and adding new perforations below with oriented perforations gun.
The results were quite encouraging with sustainable oil gain of 1400 BOPD and the detailed cost/pay back analysis indicated the payback period of only 1.5 days of production.
This successful job has opened a new era in the history of Burgan field and many other water shut off jobs may be successfully carried out without the need of rig work over. This not only will reduce the work load on rig work overs and save rig cost significantly but will also allow to increase the well productivity with a very short period of well down time.
Water Shut-Off (WSO) actions are remedial activities that are being implemented in the heavy oil N Field, with the objective of reducing the water inflow of the well by closing zones which are major contributor to the high water cut. WSO are commonly executed as a mitigation action in operating wells with previous economic value. The purpose of this study is to develop a thorough knowledge of the rate of success of WSO activities linked to the time of WSO implementation, type of well (either horizontal or vertical) and the presence or lack of PLT (Production Log Test).
Success was evaluated by reviewing the net oil production rate before and after WSO activity with the gained net oil rate being converted to US Dollars.
There is no significant difference found in the success ratios between horizontal wells and verticals. However, in the horizontal wells, 74% of the successful ones were the heel shut-offs. WSO activities are found to have a success rate of 100% if the activity is implemented within the first year of the start of high water cut. Moreover, wells with WSO implementation within the first three years of observing high water-cut have a success rate of 65%. Noticeably, the success rate decreased dramatically with time, with wells having high water-cut for seven years and up to eleven years to the time of WSO implementation. These wells show success rates of 50% and 33% for seven and eleven years respectively.
A numerical sector model and well model were created to explain these findings. During oil production because of a localized decrease in pressure, the water-oil interface may rise up and deform into a conical shape near the well. This phenomenon is known as ‘water coning’. At the time of water breakthrough, the cone is observed to be narrower than more advanced stages when the water cut has risen to higher levels. At these times, the cone has broadened and, depending on spacing between adjacent wells, has lifted the overall level of the oil/water interface, decreasing the distance between the wellbore and the water. As a result, water shutoff becomes less effective with time.
It is recommended to start WSO activities on wells within the first three years of high water-cut indications. In case there is no PLT or other data, heel shutoff for the horizontal wells have a better success rate.
Abdulhadi, Muhammad (Halliburton Bayan Petroleum) | Kueh, Pei Tze (Halliburton Bayan Petroleum) | Zamanuri, Aiman (Halliburton Bayan Petroleum) | Thang, Wai Cheong (Halliburton Bayan Petroleum) | Chin, Hon Voon (Halliburton Bayan Petroleum) | Jacobs, Steve (Halliburton Bayan Petroleum) | Suggust, Alister Albert (PETRONAS Carigali Sdn. Bhd.) | Zaini, Ahmad Hafizi Ahmad (PETRONAS Carigali Sdn. Bhd.) | Jamel, Delwistiel (PETRONAS Carigali Sdn. Bhd.) | Dolah, Khairul Arifin (PETRONAS Carigali Sdn. Bhd.) | Munandai, Hasim (PETRONAS Carigali Sdn. Bhd.) | Yusop, Zainuddin (PETRONAS Carigali Sdn. Bhd.)
In the recent low oil price environment, a cost-effective solution was proposed to use through tubing bridge plugs to perform water-shut-off (WSO) in an offshore field. The solution consisted of using slickline to set a plug with a high expansion ratio followed by a cement dump. After three WSO jobs in different wells, the method has successfully proven itself. Watercut was reduced from 100% to 0% with a minimal cost of only USD100,000.
The through tubing bridge plug used is capable of passing through 2-7/8-in. tubing and expanding into 9-5/8-in. casing. After running a Gamma-Ray log, the plug was set across the perforation interval to give the anchor contact with a rough casing surface. The top of the plug, however, was above the perforation interval and became the base for cement. Cement was then continuously dumped on top using a slickline dump bailer in a static condition until the designed cement height was reached. Static conditions ensured no movement of cement during operation. The plug differential pressure limit is directly proportional to the cement height.
The first WSO job was a complete success with watercut reduced from 100% to 0%. The second job however, was partially successful as the cement dump was not completed due to unexpected appearance of a hold-up-depth (HUD). The HUD was created by leftover cement which had accumulated at the end of the tubing. Despite the setbacks, the end result was successful in reducing water production from 1000 bwpd to 200 bwpd. The third job faced a completely different problem. The original plug fell off deeper into the well after it was set. To rectify the situation, a second plug was set at the target interval. Despite the successful execution, there was no change in watercut after the well was brought back online. Since the same method was proposed for another upcoming well, Memory-Production log (MPLT) coupled with Temperature-Noise log was performed to assess the effectiveness of the WSO. The log results confirmed that the WSO was successful and the post job water production was caused by channeling behind the casing. The results so far concluded that the through tubing bridge plug WSO method was both reliable and cost-effective. It is exceptionally suitable for zones located at the bottom of a well and can be deployed using slickline.
The paper provides valuable insight to a WSO solution which should be a first-choice option due to its relatively inexpensive cost and high reliability. The solution has proven to provide tremendous cost saving for production enhancement activity.
Carragher, Paul (BiSN) | Bedouet, Sylvain (BiSN) | Talapatra, Didhiti (BiSN) | Hughes, Andrea (BP) | Curran, John (BP) | Hou, Wei (BP) | Kosi, Orlando (BP) | Ralph, Stan (BP) | Gao, Qiang (BP) | Gracia, Jesse (BP) | Galvan, Jeanine (BP) | Calvert, Patrick (BP) | Alcoser, Luis (BP) | Dean, Doyle (BP) | Mason, David (BP)
Achieving water shut-off in gravel packed wells is challenging, particularly being able to place a mechanical barrier to flow into a gravel packed annulus. Gravel packed wells, often in deepwater environments, are often high rate wells and interventions can be costly, therefore only techniques with a high probability of success are typically sanctioned.
Many gravel pack wells are completed in multiple sands. If there are barriers between the sands that are believed to be laterally extensive, and if water is entering the lower sand, then isolating the lower sand can be a cost-effective intervention. Deepwater wells in Angola were reviewed as to whether a chemical solution or a mechanical solution would be preferred.
Providing a suitable mechanical methodology could be developed, it was felt this would provide a preferred solution. Further criteria for applying a mechanical solution were developed, to increase the chances of success. Extensive well modelling was also conducted to identify an optimum set of plugs to be placed in the well.
The operator identified a company that had an emerging technology that could offer such a solution. They then worked together to mature the technology through a series of proof-of-concept tests, through trials in Alaska, an early application in a deepwater well in the Gulf of Mexico, followed by a series of qualification tests to be ready for application in Angola. The qualification tests considered not only the mechanical configuration of the wells, but temperature, pressure and wellbore deviation. The application would require placement using a tractor, therefore testing with connecting to the relevant equipment was also incorporated in the plans for the wells.
Using a deepwater rig, several plugs were run in each well, including a meltable alloy plug. The latter plug provided a barrier to flow in both the annulus and inside the sand screens. Although not providing a barrier to shunt tubes, extensive modelling work at Cambridge university showed that it was possible to influence gravel movement in the annulus and shunt tubes, so as to maximise the pressure loss.
Two wells have had plugging systems run. The first well has reduced water cut from 100% to ca. 40% and shown a significant oil rate benefit. The second well has also shown a reduced water cut (from 70% to 40%).
Ostankov, N. A. (Samaraneftegas JSC, RF, Samara) | Kozlov, S. A. (Samaraneftegas JSC, RF, Samara) | Frolov, D. A. (Samaraneftegas JSC, RF, Samara) | Cherepanov, A. V. (Samaraneftegas JSC, RF, Samara) | Rtischev, A. V. (Samaraneftegas JSC, RF, Samara)
The PDF file of this paper is in Russian.
The paper presents the description of information system the main objective of which includes the growth in productivity at the stage of development and performance of measures to increase the energy efficiency of production. At present in view of macro-economic processes and state policy in oil and gas industry the issues of energy cost reduction and energy efficiency growth are one of the main priorities in the activity of Rosneft Oil Company. The Company now is following the focused efforts in analyzing thermal power resources, planning of measures and efficiency evaluation of performed actions. Samaraneftegas JSC has taken a decision on designing the automatic energy saving control and monitoring system to regulate and categorize the processes in the area of energy management. As the result of completed measures Samaraneftegas has designed and applied it its practical activity the software in a form of web-appendix that provides the possibility in organizing multi-user access to the specialists engaged in planning process and actualization of measures included into energy and power management sphere. The target area that covers the functional aspects of this automated system includes the following main process units and blocks as artificial lift, surface infrastructure, water shut-off jobs, etc. This software package enables to define specific sets of completed measures and efficiency evaluating methods versus their implementation at each individual above-mentioned block. Results of practical experience in applying this energy saving control and monitoring system in specific subdivisions of Samaraneftergas showed the efficiency of selected approach to creating the information flows in the areas of energy management of the Company.
В статье дано описание информационной системы, ключевой задачей которой является повышение продуктивности при разработке и выполнении мероприятий, направленных на увеличение энергоэффективности объектов. В настоящее время с учетом макроэкономическихпроцессов и государственной политики в нефтегазовой сфере вопрос снижения энергетических затрат и повышения энергетической эффективности является одним из приоритетов в деятельности ПАО «НК «Роснефть». В компании ведется целенаправленная работа по анализу потребления теплоэнергетических ресурсов, планированию мероприятий и оценке их эффективности. Для упорядочивания и систематизации процессов в сфере энергетического менеджмента в АО «Самаранефтегаз» принято решение о разработке автоматизированной системы контроля и управления энергосбережением. В результате выполненных работ АО «Самаранефтегаз» разработано и внедрено в текущую производственную деятельность программное обеспечение, представляющее собой web-приложение, которое позволяет организовать многопользовательский доступ для специалистов, задействованных в процессах планирования и реализации мероприятий по направлениям энергетического менеджмента. Предметной областью, охватываемой функционалом автоматизированной системы являются такие основные технологические блоки и процессы, как механизированная добыча, наземная инфраструктура, ограничение водопритока и др. Данный программный комплекс позволяет определять конкретные наборы мероприятий и методы оценки эффективности их проведения отдельно для каждого из указанных блоков. Результаты внедрения системы контроля и управления энергосбережением в целевых службах АО «Самаранефтегаз» свидетельствуют об эффективность выбранного подхода к формированию информационных потоков в области энергетического менеджмента предприятия.
The PDF file of this paper is in Russian.
Polyacrylamide-based formation treatment technologies have been extensively used to enhance oil recovery at the field operated by Tatneft. These are applicable under various geological conditions encountered at the Company’s fields; particularly, they may be used in terrigenous Devonian and Carboniferous deposits and carbonate reservoirs. They help to address a wide range of challenges: from water shut-off operations in production wells to conformance control treatments in injection wells. Extensive research efforts have led to development of two promising technologies: water shutoff technology relying on application of high strength polymer systems and EOR technology involving injection of high-strength cross-linked compositions to enhance production from heterogeneous waterflooded formations. These technologies are based on application of polyacrylamide and complex cross linker to produce a cross-linked polymer system (gel) exhibiting high shear strength under reservoir conditions. Laboratory studies of the effects of water composition on formation of cross-linked polymer compositions and stability of the resultant gel systems have been conducted to improve the performance of the above mentioned methods and other polyacrylamide-based technologies. The research consisted in taking samples of formation water from selected fields operated by nine oil-and-gas production departments of TATNEFT Company and a number of studies and experiments. These included determination of the composition of formation water (six-membered analysis, total salt content, content of hydrogen sulphide, and iron content); determination of the impact of water composition on viscosity and screen-factor of polymer solutions; preparation of cross-linked polymer systems with each type of analyzed formation water and examination of gel stability under near real reservoir conditions. Based on the analysis and summary of the results obtained, possible solutions for reduction of adverse effects of negative factors on the performance of cross-linked polymer systems have been through out together with recommendations on mitigation of such effects.
Применение технологий на основе полиакриламида является одним из наиболее распространенных методов увеличения нефтеотдачи на месторождениях ПАО «Татнефть». Технологии применяются в разных горно-геологических условиях месторождений компании: как в терригенных отложениях девона и карбона, так и в карбонатных отложениях. Также широк спектр решаемых задач: от ограничения притока воды в добывающие скважины до выравнивания профиля приемистости нагнетательных скважин. Разработаны технологии применения высокопрочных полимерных систем для ограничения притока воды в добывающие скважины, технология применения высокопрочных сшитых композиций для увеличения нефтеотдачи заводненных неоднородных пластов. В основе этих технологий лежит процесс получения сшитой полимерной системы (геля) из полиакриламида и комплексного сшивателя, которая обладает высокой сдвиговой прочностью в пластовых условиях. Проведены лабораторные исследования влияния состава воды, используемой для приготовления полимерных композиций в промысловых условиях, на процесс получения сшитых полимерных систем и стабильность полученных на их основе гелевых систем. Отобраны пробы пластовой воды на объектах девяти нефтегазодобывающих управлений ПАО «Татнефть». Проведены следующие виды исследований: определение состава пластовой воды (шестичленный анализ, общая минерализация, содержание сероводорода, содержание ионов железа); определение влияния состава воды на вязкость, скрин-фактор растворов полимеров; получение сшитой полимерной системы с каждым типом исследуемых вод и проверка стабильности полученного геля в условиях, приближенных к пластовым. На основе анализа и обобщения полученных результатов выбраны пути снижения влияния негативных факторов на технологические свойства сшитых полимерных систем и подготовлены рекомендации.
This study suggests a polymer nanocomposite gel system that can effectively be used as water shutoff material for high temperature reservoirs. Based on nanotechnology, a novel cost effective and ecofriendly polymer gel formulation is presented. This newly developed material extends the temperature limitations for high temperature reservoirs.
In particular, this paper reports an innovative graphene-based zirconium oxide nanocomposite as a crosslinker for water shutoff utilizing polyacrylamide polymer and its derivatives. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were utilized to characterize the fabricated gel samples. The microstructure of the polymer nanocomposite gel was analyzed using scanning electron microscopy (SEM). The new developed formulation of the nanocomposite gel fluid was evaluated by rheometer tests at different ranges of pH (temperature up to 330°F) to study the gelation behavior and performance of the system for water shutoff application. Furthermore, the newly developed fluid system was injected into core samples to evaluate the ability of the gel to resist extrusion and determine the strength of the treatment under reservoir conditions. The polymer nanocomposite gel showed surprising mechanical properties with extraordinary thermal properties at elevated temperature. The TGA result revealed a remarkable shift of three main decomposition regimes at high temperatures, which confirms the enhancement of thermal stability of the synthesized nanocomposites polymer gel. The XRD pattern of the polymer gel had peaks that confirm the existence of the graphene and zirconium oxide in the system. The SEM images showed that this new class of polymer gel has a homogeneously distributed 3D network microstructure. The small size of the gel grid pores made the network structure thermally stable and firmly locked water within the gel even under high temperatures. The addition of sodium carbonate could also elongate the gelation time from ~70min. to 104 min at high temprature (330°F). The core flooding results showed a significant drop in water production for the sandstone matrix core that had higher permeability before the treatment.
The developed nanocomposites polymer gel with enhanced mechanical and thermal stability can significantly reduce excess water production within high temperature reservoirs at lower costs than the currently available polymer gels.
Water production in oil/gas wells can be a limiting factor when it exceeds a certain limit in the producing well. Therefore, water control has become an essential objective for oil field operators. According to Bailey , there are around 210 million barrels of water accompanying every 75 million barrels of oil, thus water handling costs are high. For example, in a well producing oil with 8% water cut, the cost for handling water can be as high as 4 US dollars per barrel of oil produced. In some depleted oil fields in the USA, the ratio of water-to-oil is closercloser to 9:1. In addition, water production can cause operational problems, such as equipment corrosion, scale formation, higher tendency for emulsion, and leakages . Water can flow within the production well because of near-well bore problems or reservoir related problems , . These problems will eventually reduce the economic life of the producing oil wells. Fig. 1 depicts some of the sources of unproductive water production . Based on extensive reservoir and completion engineering lessons and investigation of several field applications, several types of water problems ranked and classified from least to most difficult are shown in Fig. 1 (1-10). Moreover, according to Flores et al (2008) , water production types can be classified into three categoriescategories depending on the problem type (PT). These type of problems are defined according to the water flow path instead of symptoms. The problem types can be classified into three categories including t) that is ype (A): open flow path; type (B): edge water from water flood or naturalnatural aquifer; and type (C): bottom waterproblems . Table 1 lists the type of problems and their categories whereby the first three listings are consideredconsidered to be the simplest problems.
Injection of blocking gels in the near wellbore of producer wells is a technique employed for water production control. A proven and effective alternative to control this water excess is the application of crosslinked gels. Water shut-off (WSO) treatments efficiency depends on several aspects such as reservoir fluid flow patterns, rock petrophysics, formation heterogeneities and gel characteristics. Although experimental laboratory tests previous field implementation, are many times underestimated, they provide valuable information that increases the chances of success. Integrating lab results with reservoir and field data creates a proper scenario that diminishes the uncertainties during field implementation. It is also crucial the support of a multidisciplinary team work while injecting the WSO tretament. This paper presents a successful water shut-off treatment specially designed for high temperature, applied in a production well located in Vizcacheras field, Mendoza Agentina.
Galimov, I. F. (Tatneft PJSC, RF, Almetyevsk) | Gubaidullin, F. A. (Kazan (Volga) Federal University, RF, Kazan) | Vakhin, A. V. (Kazan (Volga) Federal University, RF, Kazan) | Isaev, P. V. (Kazan (Volga) Federal University, RF, Kazan)
The PDF file of this paper is in Russian.
The article reviews the geological structure and analyzes the current state of development of the South Romashkinskaya area of Romashkinskoye deposit. The main objects to be developed are the reservoirs а, b1 и b2 of the Pashian Horizon D1. The South-Romashkinskaja area is a mature oil field. Deposit depletion is 86.1% of the initially-recoverable reserves. Oil recovery factor is 0.458, at project expected value of 0.475. The area has entered the final stage of development. The development is characterized by a slow decline in oil production (less than 2% of the initially-recoverable reserves), a large water cut and a complete transition to mechanized operation. The injection of water in order to maintain reservoir pressure in the area started in 1955. The amount of injected water increased each year until 1970. In this article, the conditions for the application of the hydrofracturing of the reservoir, the conditions for selecting the wells to carry out implement this technology were considered. The process of the hydrofracture was calculated and the technological efficiency of its application was determined. In some cases, especially at the late stage of the development of the deposit, the application of the HFR method solves the problems of restoring the hydrodynamic link to a productive reservoir in the extractive wells and contributes to the fuller development of oil reserves. As a result of hydrofracturing application, a double increase in oil debits has been received. It is shown that the high efficiency of this method, in the context of the considerable deposition of stocks, low debits, and high water cut, can be provided in synergy with the technology of water shutoff treatment. Authors have identified basic requirements to the wells for hydrofracturing. Work also includes an analysis of the technological performance of the hydrofracturing in the producing wells that allows to intensify oil recovery.
Рассмотрены геологическое строение и текущее состояние разработки Южно-Ромашкинской площади Ромашкинского месторождения. Основными разрабатываемыми объектами являются пласты а, б1 и б2 пашийского горизонта Д1. Южно-Ромашкинская находится на заключительной стадии разработки. Выработка нефти составила 86,1 % начально-извлекаемых запасов (НИЗ), коэффициент извлечения нефти – 0,458 при проектном 0,475. Площадь вступила в завершающую четвертую стадию разработки. Разработка характеризуется медленным снижением добычи нефти (темп отбора от НИЗ – менее 2%), значительной обводненностью продукции и полным переходом на механизированный способ эксплуатации. Закачка воды с целью поддержания пластового давления на площади осуществляется с 1955 г. В статье рассмотрены условия применения гидроразрыва пласта (ГРП). В ряде случаев, особенно на поздней стадии разработки, применение ГРП позволяет восстановить гидродинамическую связь добывающих скважинах и продуктивного пласта-коллектора и способствует более полной выработке запасов нефти. В результате проведения ГРП дебит нефти увеличился в 2 раза. Показано, что высокую эффективность ГРП в условиях значительной выработанности запасов, низких дебитов, высокой обводненности продукции обеспечивает его комплексирование с технологией изоляции водопритоков. Определены основные требования к скважинам-кандидатам для проведения ГРП на участках указанного месторождения со сложными горно-геологическими условиями залегания и длительным сроком разработки нефтяных пластов. Проведен анализ технологической эффективности ГРП в добывающих скважинах.